In accordance with the requirements of citation databases, proper citation of publications appearing in our Quarterly should include the full name of the journal in Polish and English without Polish diacritical marks, i.e. "Eksploatacja i Niezawodnosc – Maintenance and Reliability".

Task „Implementation of procedures ensuring the originality of scientific papers published in the quarterly „Eksploatacja i Niezawodność – Maintenance and Reliability” financed under contract 532/P-DUN/2018 from the funds of the Minister of Science and Higher Education for science dissemination activities.

Examination of the influence of cross-impact load on bend strength properties of composite materials, used in aviation

Fibre reinforced composites are often used in airplane structures because of their specific strength. One type of the materials are layered composites (laminates) applied inter alia in aircraft’s covering production. Laminate is susceptible to damage resulting from impacts, the effect of which is usually invisible during macroscopic observation. The article presents results of a preliminary examination of layered composites obtained from an airplane element loaded impactly with low energy. During testing, pieces were loaded with 2.5; 5 and 10 J energy and then they were put on bend tests. The material bending strength after a shock load with 2.5 and 5 J energy remains almost unaltered, but for 10 J energy, it decreases by more than 30% in comparison to undamaged material. As a result of the examination, it was ascertained that in all cases the exact location of the damage could be difficult to find, which is a significant maintenance problem.

The aim of the study was to evaluate the possibility of using multilayer structures for light armour, in which the elements of the ceramic type SiC and Al2O3 were bonding by adhesive joins with antiballistic polyethylene and aramid fabrics. Ballistic resistance shells was determined using for this purpose the test stand constructed on the basis of helium gun and high-speed camera. It has been shown that the laminated structure composed of thin metal layers and aramid fabrics as well as polymer composites made of aramid fabric has lower ballistic resistance than loose fabric packs. It was also demonstrated the functionality of the use of the ceramic component as a separate package, which the ceramic plates are adhesive bonded between the two layers of sheet metal. There is also evidence that fabrics composed of thin layers of material poorly connected with each other, should not be adhesively bonded to the ceramic. It proposed the preparation of specimens, which best reconstruct the load of ceramic plates adhesive bonded to fabric, which are made of lightweight bulletproof vests and ballistic panels.